Chalk lines are commonly used in the construction and building trades for marking measurements. It is common practice in construction layout to apply lines of differing colors and widths to differentiate the purpose of marks made. Repairing broken chalk line on a single reel can take time away from constructive working time. For these and other reasons, it is a common practice for builders familiar with such methods to carry multiple chalk line reels. Likewise, the advantage of integrating a winding advantage to collect deployed line back onto the chalk line spool is well established in the art and practice.
A number of dual and multiple reel chalk line inventions may be found in the prior art, typically embodied as an arrangement of spools in which a single handle may drive a stack of axially aligned spools and allow selective engagement of a spool through various means. However, these arrangements have certain disadvantages. For example, stacked spool arrangements may result in an over-wide package solution. Additionally, stacked spool arrangements necessitate the need for additional internal walls to separate chalk volumes.
Alternately, prior art spools may be mounted on separate axis and coupled to distinct means so that the use of any spool is selected by changing from one handle to another. The need to supply separate drive means for each spool significantly increases the necessary production cost of a multi-reel product and is generally inconvenient to use.